DE3046909A1 - LASER - Google Patents

Description

R 4454

laser

The invention relates to a laser, namely
especially a free electron laser.

Since the first demonstration of the laser concept, there has been great interest in developing a
High-power laser that continuously runs over a
can be tuned across a wide frequency range.
High power lasers tunable in this way could be used extensively in industrial chemical applications to provide energy for specific reactions. For example, such a laser could be used as a source to clean exhaust gases from combustion by selectively breaking down toxic substances; or such a laser could

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for cleaning raw materials for chemical processes can be used by selective destruction of contaminants such as those impurities that affect catalysts used in coal gasification processes.

Since the gas molecular laser became available, high outputs have been achieved. Gas molecular lasers are however unable to continuously tune over more than a very limited range of frequencies and only generate a certain set of frequencies, which depends on the gaseous laser medium. The concept the extraction of coherent optical radiation from a stream of relativistic electrons, i.e. the "free Electron Laser "was first introduced by J.M.J. Madey, Stanford in 1971. J.M.J. Madey et al later about the laser effect from stimulated bremsstrahlung with the Stanford Linear Accelerator, cf. in addition Phys. Rev. Letts., 38, 892 (1977). The collaboration of Columbia University Laboratory and Naval Research Laboratory revealed a laser based on stimulated Raman scattering by free electrons, as shown in the following Reference has been reported: D.B. McDermott et al., Phys. Rev. Letts., 41, 1368 (1978). The report of this Results on the "free electron laser" have generated considerable interest as it is possible that free Electron lasers are capable of extraordinarily high outputs at low costs and are continuously tunable Supply frequency.

In addition to the continuously tunable frequency and

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the potentially high output power of the free electron laser, this has the additional advantage that no laser medium such as a fluid, Gas or a solid is present, which tends to increase performance and optical resolution limit, through linear and non-linear optical deformation effects in the laser medium.

Also, flow systems as well as the power to pump the gaseous molecular laser medium of the gaseous and liquid molecular lasers avoided.

Other use cases for the high power generating free electron lasers are military applications on ships that defend against missiles, the submarine connection and detection, the power transfer to satellites and possibly even the propulsion for maneuvers in space. To the above Industrial laser use cases also include the following: laser isotope separation; Laser machining and possibly power transmission from solar space stations to earth.

So far, however, the various proposed free electron laser systems have only had low efficiencies demonstrated or reported, i.e. in laser systems designed for the generation of shorter wavelengths as the near infrared (IR) have been proposed. The DC acceleration / deceleration concept achieved high efficiencies at longer wavelengths (for example λ ίνΊΟ µm); compare the following

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Reference / L.R. Elias, Phys. Rev. Letts. 42, 977 (1979).

It is accordingly a considerable input power as well considerable capital cost required to run free electron lasers at short wavelengths (e.g. $ 1 µm) and to operate high output powers, which necessarily necessitates the use of the free electron laser for affects various applications as many of these applications require shorter operating wavelengths.

The invention has therefore set itself the goal of providing an improved free electron laser, in particular has a high degree of efficiency and is reliable in operation.

Another object of the invention is to provide a free electron laser that has high outputs at high outputs Can generate efficiencies and with wavelengths shorter than the near IR.

Another object of the invention is an improved electron beam power system to be provided for free electron lasers.

Further advantages, goals and details emerge from the claims and from the description of exemplary embodiments based on the drawing.

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The invention overcomes the disadvantages and limitations of the prior art through an improved free Electron laser as well as an improved electron beam power system for a free electron laser,

The free electron laser according to the invention has the following: means for generating an electron beam, wiggler means for inducing transverse oscillations in the electron beam, means for guiding the electron beam in a closed loop, and acceleration / deceleration means (catalac) to accelerate the Electron beam in an initial pass through the acceleration / deceleration means and for deceleration of the electron beam in a second pass through the acceleration / deceleration means to extract energy to extract the electron beam and the energy in acceleration fields of the acceleration / deceleration means to transform.

In addition, an electron beam power system for a free electron laser is provided according to the invention, and with a wiggler to extract energy from a beam of electrons with a predetermined energy level for generating coherent radiation, the following means also being provided: means for generating the beam of electrons, means for directing the beam of electrons in a closed loop, and acceleration / deceleration means (catalac) to accelerate the beam of electrons to the predetermined one Energy level for the system on the wiggler and for the delay

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the beam of electrons emerging from the wiggler to extract energy from the beam of electrons and the energy in acceleration fields of the acceleration / deceleration means to transform.

The advantage of the present invention is that coherent optical radiation with shorter wavelengths than the near IR can be generated in a free electron laser, this radiation being continuous over can be tuned over a wide range of frequencies. The invention produces a high output power at an economical cost in a device using HP acceleration technology that is well developed and reliable in operation.

In the following, exemplary embodiments are based on the drawing described; in the drawing shows:

Fig. 1 is a schematic diagram of the interaction region of the free electron laser;

Figure 2 is a schematic diagram of a single pass or single pass free electron laser;

Fig. 3 is a schematic diagram of a free

Electron laser device with storage ring;

Figure 4 is a schematic diagram of a DC recovery free electron laser device;

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Fig. 5 is a schematic diagram showing the

Concept of the invention illustrated, and using an acceleration trajectory RF acceleration / deceleration energy recovery device (catalac);

Figure 6 is a conceptual diagram of the operation of the free electron laser according to the preferred embodiment of the invention;

7 is a schematic diagram of components of the Catalac-free electron laser according to FIG Fig. 6;

8 shows a graph of the electron density as a function of the electron energy for electrons emerging from an exemplary wiggler for the invention;

Figure 9 is a schematic diagram of a Catalac-free electron laser in use an auxiliary catalac;

Fig. Io is a schematic diagram of a Catalac-free Electron laser, using an injector linac according to a preferred one Embodiment of the invention;

Figure 11 is a schematic diagram of a Catalac-free electron laser in use a downstream linac;

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Figure 12 is a schematic diagram of a catalac free Electron laser, using a catalac and an auxiliary catalac, placed in line with the laser beam;

Figure 13 is a schematic diagram of a Catalac-free electron laser in use an auxiliary Catalac and an offset wiggler arrangement;

14 is a schematic representation of a Catalac-free electron laser, for illustrative purposes the use of numerous stages of auxiliary catalac for extraction numerous levels of electron beam energy;

15 is a schematic diagram of a ring resonator;

Fig. 16 is a schematic diagram of a configuration using the Catalac-free electron laser as a laser amplifier for a main oscillator laser.

Fig. 1 shows the free electron-laser interaction region or zone, the coherent radiation according to the invention generated and amplified. A wiggler field Io is a spatially oscillating (oscillating) static magnetic field, which is indicated by a wiggler described in U.S. Patent 3,822,410. The title of this US patent application reads "Stimulated Emission of Radiation in

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Radiation in Periodically Deflected Electron Beams "; issued on July 2, 1974 to Madey et al. The optical laser field 12 runs transversely to the optical axis 14, as shown in FIG comes and consequently works on electron beam 16, the electrons of electron beam 16 must have a velocity component perpendicular to the optical axis. The wiggler field Io builds up an alternating periodic magnetic field in order to induce undulations in the electron beam 16 as it passes through the wiggler, whereby a transverse Velocity is induced in the electron beam 16, which allows the interaction of the laser optical field 12 with the electrons of the electron beam 16. As a result of this interaction, some of the electrons of the electron beam 16 are accelerated by the interaction of the electron beam 16 with the laser optical field 12, while others are delayed, un d depends on the initial phase of the electrons in the optical field 12. This acceleration and deceleration of electrons causes the electrons of the electron beam 16 to form bundles or tufts. When the bundles of electrons oscillate in the Wiggler field Io, the bundles come into a phase relationship with respect to the optical field in such a way that the optical field decelerates the bundles and extracts energy. In-phase occurs when the optical wavelength, the electron energy and the wiggler field as well as the wiggler period are set in the correct manner. The spatial period of the wiggler generating the wiggler field Io and the energy of the electrons of the electron beam 16 determine the frequency of the optical coherent radiation generated by the free electron laser. The nominal relationship between the Wiggler wave number (k _w )

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and the optical (signal) wavenumber (k) is the following:

^k w ^{= k} s ^{(1 +} e ² B ² / m ² c ² ) / 2 _K ² ,

where c = the speed of light

m = the remaining mass of the electron

e - the electron charge

B = the magnetic field of the wiggler

ν = the relativistic mass factor,

this state is called the resonance state. An electron beam that moves through a wiggler with uniform Wave number k and magnetic field B moves and the

Sufficient resonance conditions will not emit any radiation, but will form bundles with the optical wavelength brought. If the wiggler wave number is slightly lower than the resonance condition, the electron beam will both form bundles and rays, whereby the energy of the radiation field is increased. In the following Reference is an example of a helical coil wiggler for generating the corrugated wiggler magnetic field Io described: D.A.G. Deacon et al., "Phys. Rev. Letts., 38, 892 (1977). In addition, a set of guide rings that generate a wave in a solenoidal field is to generate the wiggler field Io, described in the following reference: D.B. McDermott et al., Phys. Rev. Letts., 41, 1368 (1978). Furthermore, a suitable arrangement of permanent magnets is suitable to create a wiggler field Generate Io.

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Fig. 2 schematically shows a single passless electron laser device in which an electron beam 18 is accelerated in a Linac 2o or other acceleration device and applied to a wiggler is where a fraction of the electron beam energy is extracted as laser energy. Because the extraction efficiency If the laser energy through the wiggler is low, the overall efficiency of the single pass device is according to FIG. 2 an even lower value. Since the total system costs depend on the input power, the possible solution according to FIG. 2 is expensive, despite its simplicity, in order to achieve a high output laser power to reach.

FIG. 3 schematically shows a storage ring device which utilizes the energy generated in the from the wiggler 26 exiting electron beam 22 utilizes remaining energy, namely by re-accelerating the electron beam 22 in the Linac 24 by a size equal to the energy extracted by the wiggler. This is done by reinserting of the electron beam 22 emerging from the wiggler 26 into the input of the Linac 24 for acceleration achieved. The disadvantage of the storage ring device shown in Fig. 3 is that the torque distribution of the Electron beam through the free electron laser wiggler is widened. This means that some electrons are delayed more than others, which is due to their phase in relation to the laser field depends. With this broadening of the moment distribution, synchrotron radiation must then be used elsewhere in the Recirculation ring 28 are attenuated before the electron beam '22 can be accelerated again and again in free electron laser wiggler can be used. The complexity of a suitable storage ring would be a problem

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require extensive capital investment and in any case the synchrotron losses for the beam narrowing significantly degrades the overall efficiency values that eventually can be obtained.

Fig. 4 shows a DC voltage recovery device, which avoids the problems of electron beam quality degradation by Use of a DC electrical feedback system such as that disclosed in the above referenced US Pat L.R. Elias was described. The energy recovery is achieved by a DC voltage accelerator, using a back-biased collector to retard the electron beam after it has gone through the wiggler. Only a small power supply is required to keep the electricity at its original level bring back high potential. The DC voltage recovery apparatus shown in Fig. 4 is however, to a low electron beam energy and accordingly to longer laser wavelengths, for example λ *, 2.10 um restricted.

Fig. 5 illustrates the RF acceleration / deceleration energy recovery device according to the invention. The main components for the representation of the invention Conceptually are the following: an injector 3 $, a Catalac (catalytic linac) 4o and a wiggler 46. Beam transport mechanisms direct the electron beam generated by the injector 38 in a closed loop through the Catalac 4o. The Catalac 4o acts as a catalyst insofar as it conditions the electron beam

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provides for laser action in the Catalac-free Electron lasers are required without incurring any net radiation exposure themselves, thereby creating the name "Catalac" (catalytic linac) results.

In operation, the injector 38 generates an electron beam 41 which, during an initial pass through the Catalac 4o is accelerated. The electron beam is then passed through wiggler 46 which extracts laser energy. The electron beam 48 emerging from the wiggler 46 is passed through the Catalac 4o, out of phase with it the accelerating fields of the Catalac so that energy is extracted from the electron beam 48 and converted into energy of the accelerating fields of the Catalac 4o is transformed in order to accelerate the electron beam 41. Delayed electrons of the electron beam 48 are then emitted into beam waste means 42. Hence the problems the electron beam energy propagation, as it occurs in the storage ring device of FIG. 3, avoided here, since the electrons are not reused, as was the case with the device according to FIG. 3.

Fig. 6 shows in more detail the operation of the RF acceleration / deceleration energy recovery device shown in Fig. 5; which is known as a Catalac-free electron laser. The invention used an RF linac system in which RF fields, such as microwave fields, are applied to resonant cavities, to accelerate the electron beam. The technology of the HF linac systems is well developed and such Systems have a high degree of efficiency and a high

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reliability shown. For purposes of illustration it will be using suitable parameters a free electron laser with an average power of 10 MW and 1 lim wavelength.

As shown in Fig. 6. he creates an injector 2 MeV electron beam 52, which via conventional mechanisms is entered into the Catalac 54. The Catalac 54 has any number of conventional RF powered Accelerators, as described, for example, in the following literature: "Computer Design 905 MHz Proton Linac Cavities" by Harry C. Hoyt et al., Described in Rev. of Sci. Instruments, Volume 37, No. 6, pp. 755-762, June 1966, "Coupled Resonator Model for Standing Wave Accelerator Tanks" by D.E. Nagle et al., Rev. of Sci. Instrums, Volume 38, No. 11, pp. 1538-1587 Nov. 1967 and "Standing Wave High Energy Linear Accelerator Structures "by E.A. Knapp et al., Rev. of Sci. Instrums, Volume 38, No. 7, pp. 979-991, July 1968. Or but the Catalac has the washer and washer structure as described in the following references is: "High Energy Accelerator Structures for High Gradient Proton Linac Applications" by J.J. Manca et al. in IEEE Transactions on Nuclear Science, Volume NS 24, No. June 3, 1977 and "Experimental and Calculated RF Properties of the Disk and Washer Structure "by J, M. Potter et al., IEEE Transactions on Nuclear Science, Volume NS 26, No. June 3, 1979. Of course, any suitable RF accelerator can be used for acceleration in accordance with the invention of multiple amperes (peak current) electron beams, such as the cavity structure according to

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the following reference: "Beam Test With S-Band Standing Wave Accelerators Using On-Axis Couplers" by SO. Schriber et al. In Proceedings of 1972 Proton Linear Accelerator Conference, Oct. lo-13, 1972.

The injector 50 includes any suitable injector that generates multxamp currents, such as the injector used in the Stanford Linear Accelerator as described in the following reference: "The Stanford Two-Mile Accelerator "by R.B. Neal, W.A. Benjamin Inc., New York, 1968, Chapter 8, Injector, pp. 241-271. Further suitable injectors for use according to the invention are described in the following reference: "Performance of 14o MeV High Current Short Pulse Linac at ORNL" by N.C. Pering et al., In IEEE Transactions on Nuclear Science, Volume NS 16, No. 3, June 1969 and "Subnanosecond High Intensity Beam Pulse" by G. Mavrogenes et al. In IEEE Transactions on Nuclear Science, Volume NS 2o, No. June 3, 1973.

The one generated by the injector 50 - cf. on this again Figure 6 - Electron beam 52 (full circles) is input to Catalac 52 with a phase relative to the RF acceleration fields, which is the acceleration of the electron beam 52 in the Catalac results in 54 on loo MeV. The electron beam 52 exiting Catalac 54 becomes then passed using conventional beam transport systems through wiggler 56, which is equipped with an optical resonator is aligned, which has reflectors 58 and 6o. After energy extraction from electron beam 52 in FIG in the manner disclosed in Fig. 1, the exiting electron

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ray 62 (open circles) and fed back into the Catalac 54, so that the bundle roughly speaking 180 ° out of phase with the microwave acceleration fields in the Catalac 54. This causes the electrons of the exiting electron beam 62 are delayed in order to reduce the energy of the electrons of the electron beam 62 to the acceleration fields of the Catalac 54, this energy being used to accelerate the electron beam 52 is used. The low energy ones retarding electrons 63 exiting the Catalac are separated by beam 52 and at 64 eliminated by an electron spectrometer or other suitable device for separating the low-energy electrons from the high energy electrons, as described, for example, in the following literature reference is: "Focussing of Charged Particles", edited by Albert Septier, Volume 2, Section 4.2, Academic Press 1967, New York, USA.

Figure 7 is a perspective view of the various Components of the Catalac-free electron laser according to FIG. 6. Klystrons 68 generate microwaves RF energy to generate the acceleration and deceleration fields of the Catalac 54 in a conventional manner, as shown in the following Reference is described: "Klystrons and Microwave Triodes" by Donald W. Hamilton, Julian R. Knipp, J.B. Horner Kuper, McGraw-Hill Book Company, Inc., New York, 1948. Beam transport magnets 7o and 72 guide the electron beam in the closed loop pattern in connection with bending magnets 74 and 76.

Fig. 8 is a graph of electron density;

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dependent on the electron energy for electrons emerging from a typical tapered wiggler for use in accordance with the invention. According to the concept of the tapered wiggler, the wiggler wavenumber and wiggler field are changed in such a way that a significant number of electrons are trapped in a potential source or sink and these are coherently decelerated. This is achieved by using a wiggler which has a decreasing spatial period, whereby the spacing in each successive magnetic field is "matched" to the energy of the electron emerging from the previous magnetic field. As each set of magnetic field lines extracts energy from the electrons, successively shorter spatial periods of the magnetic fields are used to coherently decelerate the electrons in the "tapered" wiggler. Such a tapered wiggler is capable of extracting 5% or more of the energy of the beam or more. In addition, the distribution function of the electrons emerging from the wiggler is compatible with the Catalac deceleration device, since distinguishable energy peaks are generated, as shown in FIG. In other words, the exit beam distribution function, shown in FIG. 8, is dominated by two peaks which represent two groups, namely a first peak of electrons (at a 100 MeV peak) which run relatively unaffected by the wiggler and a second group of electrons (85 MeV peak), the "captured and ¹¹ were strongly delayed in the moving force field, generated by the laser and the tapered wiggler, as described above.

9 shows an arrangement according to the preferred exemplary embodiment of the invention to extract a maximum

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Energy quantity from the energy distribution function according to Fig. 8. Injector 78 generates a low energy beam, for example 2 MeV injected into Catalac 8o via bending magnet 82. That is Catalac 8o designed such that it accelerates the electron beam generated by the injector 78 by 83 MeV, by one To generate output beam 83 with 85 MeV. The 85 MeV beam 83 passes through electron spectrometer 84 and is in a supplementary or auxiliary Catalac 86 entered, which the 85 MeV beam 83 is further accelerated to a 100 MeV beam 89. The 100 MeV ray 89 then passes through that Electron spectrometer 88 and is via conventional beam transport devices (not shown) passed to the bending magnet 9o, which wigglers the electron beam 89 conducts, which is arranged within the interaction zone. Output optics 94 and reflector 96 feed the coherent one Radiation back through the interaction zone for the purpose of amplification.

The electron beam 99 emerging from the wiggler 92 has an electron energy distribution as shown in FIG. 8 is shown. The electron beam 99 is driven by the bending magnet 98 and conventional beam transport devices (not shown) directed to the entrance of Catalac 8o. The electron beam emerging from the wiggler 92 99 with the electron energy distribution according to FIG. 8 is entered into the Catalac 8o in such a way that the The bundles are approximately 180 ° out of phase with the acceleration fields of the Catalac 8o. The Catalac 8o extracted 83 MeV from the 100 MeV and 85 MeV electron energy distribution peaks of the electron beam 99, around 17 MeV and To generate 2 MeV peaks in the electron beam 81 leaving the Catalac 8o. Those from the electron beam 99

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extracted energy is converted directly into energy of the acceleration fields of the Catalac 80 transformed. As a result, the combined electron beam 81 and 83 made from exiting the Catalac 80, a high energy spike at 85 MeV from the accelerated 2 MeV beam from injector 78 and low energy peaks at 17 MeV and 2 MeV.

The electron spectrometer 84 separates the 2 MeV peak, the is eliminated in the radiation discharge I00. The remaining one Electron beam peaks at 85 MeV and 17 MeV. The 85 MeV tip is on loo MeV in the auxiliary Catalac 86, like described above, while the 17 MeV peak is applied to the auxiliary Catalac 86 in such a way that the electron beams roughly 180 ° out of phase with the Acceleration fields of the auxiliary Catalac 86 are. As a result, 15 MeV will be extracted from the 17 MeV peak in order to to generate a 2 MeV peak beam, which is from the electron spectrometer 88 is separated and eliminated in the jet remover 1o2. The remaining one, from the electron spectrometer Electron beam 89 exiting 88 has a single peak at 100 MeV. The ones from the 17 MeV peak in the auxiliary Catalac Energy extracted 86 is transformed directly into energy of the acceleration fields of the auxiliary Catalac 86.

The arrangement according to FIG. 9 therefore provides a device for extracting energy from two separate electron energy distribution peaks of the electron beam 99 emerging from the wiggler 92. The only important losses in the System are the 2 MeV rays, applied to the radiation

eliminated "he I00 and 1o2 and the power losses in the

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Acceleration structures. In addition, the electrons that have passed through the wiggler 92 will not be in the Rather, they are reused in a manner similar to that used in the storage ring device of Fig. 3 Delayed in the Catalac 8o and auxiliary Catalac 86 and eliminated in the radiation eliminators 1oo and 1o2. This eliminated many problems of energy distribution in the electron beam applied to the wiggler 92.

Typical parameters for a 10 MW CW system such as this shown in Fig. 9 are summarized as follows:

wavelength 1 um Micro-pulse length 85 ps Micro pulse repetition time 14 ns Average performance 1o MW Top performance 1.5 GW Peak intensity 50 GW / cm ² Saturated gain per pass 100% Initial mean electron energy 100 MeV Finally reached mean Electron energy 94 MeV Extraction efficiency 6% Finally trapped electrons energy 85 MeV Capture fraction 4o% Maximum acceptable energy distribution 0.89% while capturing Wiggler length 16 m Wiggler period 4-2.9 cm Magnetic Induction (rms) 2.7-3.7 kG

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ZS

Resonator length
Mirror diameter Average intensity incident on the mirrors Peak intensity, incident on the mirrors
Mirror reflectivity Average thermal load on the mirrors Acceleration frequency Acceleration in the injector Catalac Acceleration (deceleration) in the POLAC (auxiliary Catalac) Total acceleration Average current Peak current
Micro bundle length
Injection Subharmonic Electron Beam Diameter Energy Distribution (Propagation) Emittance

Equivalent energy distribution due to emittance

Effective total energy distribution Total structure length (Catalac + POLAC) Total structure power loss (copper losses)
Injection power loss (copper losses)

Electron energy at the disposal device

Losses in the disposal devices

32o m 8 cm

2oo kW / cm

3o MW / cm 99%

2 kW / cm ² 358 MHz 2 MeV

15 MeV 1oo MeV 1.6A 25OA 85 ps (11.5 °)

1.4 mm o.5% 0.4 mm-mrad

0.44% 0.67% 100 m

2.5 MW o.1 MW 2 MeV 3.2 MW

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Beam load in the POLAC (= laser power) 1o MW HF-to-laser efficiency 63% Klystron efficiency 65% DC voltage-to-laser efficiency 41%

Fig. 1o shows a construction that may be simple is in construction but is somewhat less effective than the system of FIG. Fig. 1o shows an injector 1o4, the to a 2 MeV beam, which is then sent to an injector Linac 1o6 is applied, which accelerates the injector beam to 17 MeV. The 17 MeV beam is sent to Catalac 1o8 applied, which accelerates the beam to 100 MeV. The 100 MeV beam passes through the electron spectrometer 11o and is applied to the interaction zone by bending magnet 114 directed where wiggler 116 is located. The wiggler 116 extracts energy from the 100 MeV electron beam and produces an electron energy distribution function as shown in Fig. 8 with peaks at 100 MeV and 85 MeV. The exiting electron beam is then directed via bending magnet 118 to the entrance of Catalac 1o8. The exiting electron beam 12o is applied to Catalac 1o8 in such a way that the electrons are out of phase at 180 ° bundle with the acceleration fields in the Catalac 1o8. The Catalac 1o8 extracts 83 MeV from the 100 MeV and 85 MeV peaks to create an output beam with peaks at 2 MeV and 17 MeV. Again, the exiting electron beam 12o extracted energy directly in energy of the acceleration field of the Catalac 1o8 transformed. The 2 MeV and 17 MeV peaks are then extracted from electron beam 122 via electron spectrometers 11o extracted. A through exit reflector 128 and total

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The optical resonator formed by the reflector 126 generates an optical feedback for amplification to the laser output 13o to generate. The overall efficiency of this device is based on calculations and figures for the 10 MW device of the type described above, 21%. Optimizing the parameters would produce a higher degree of efficiency.

11 shows an alternative embodiment of the invention. As shown in FIG. 11, an injector 132 sets a Electron beam 134 with an energy level of 2 MeV at Catalac 136. Catalac 136 accelerates beam 134 to 100 MeV to generate 14o electron beam with 100 MeV. The bending magnet 142 directs the electron beam 14o through Wiggler 144, which is designed such that up to 6 MeV extracted from the electron beam 14o to the Generate electron beam 146. The electron beam 146 is applied to the downstream Linac 148 (Post-Linac), which accelerates electron beam 146 by 6 MeV. Since the electron beam 146 has two electron density peaks at approximately 94 MeV and 100 MeV, electron beam 152 has two peaks at approximately 100 MeV and 1o6 MeV. The electron beam 152 is then injected into Catalac 136, roughly speaking at 180 out of phase with the accelerating fields so that 98 MeV are extracted, around two peaks at approximately 2 MeV and generate 8 MeV. As a result, the electron beam 138 exiting Catalac 136 has peaks at approximately 2 MeV, 8 MeV and 100 MeV. An electron spectrometer (not shown) separates the low energy electrons with energy distribution peaks at approximately 2 MeV and 8 MeV of the 100 MeV electrons of the electron beam 14o and conducts

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electron beam 154 in beam eliminator 156.

Fig. 12 shows an alternative arrangement of elements, where the wiggler 158, auxiliary Catalac 16o and Catalac 162 are arranged in line with the optical axis of the optical resonator comprising optics 164 and optics 166. Again, the same parameters as in the device according to FIG. 9 are used on the device applicable according to FIG. 12. The advantage of the device according to FIG. 12 is that the arrangement of the Wigglers in line with the Catalac ^ and the auxiliary Catalac 16o avoids the need for an achromatic and an isochronous radiation transport system must be provided between the wiggler 158 and Catalac 162. An achromatic one and isochronous radiation transport system is created as a result of angular divergence and energy distribution in the electron beam, required by the wiggler in the device in FIG. By the device according to Fig. 12 avoids the engineering problems of such ray transport due to divergence which result from such a system as a result of the different energy levels located electrons and because of the angular divergence, caused in these electrons by the Wiggler 158. The disadvantage of the arrangement according to FIG. 12, however, is that the projection of the optical beam 168 by Catalac 162 and auxiliary Catalac 16o is required.

Fig. 131 shows an alternative embodiment where the optical axis 17o of the optical resonator is offset from Catalac 172. FIG. 13 is similar to FIG. 9 and can be designed in such a way that the same parameters as in

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Fig. 9 can be applied. The advantage of the device according to FIG. 13 is that problems of beam guidance after the exit of the electron beam 178 from the wiggler I80 due to the angular divergence and the energy distribution, introduced by the Wiggler I80, due to the minimal change in direction of electron beam 178.

14 shows a Catalac-free electron laser according to the invention, similar to the device according to FIG except that additional levels of auxiliary Catalacs are added to further extract energy from a more complex energy distribution generated by wigglers 182. In operation, injector 184 generates a low energy electron beam that into which Catalac 186 is fed via bending magnet 19o. The electron beam is then in Catalac 186 accelerates and is included in a number of auxiliary Catalacs, such as auxiliary Catalac 192, within a Series of stages such as the first stage 194, a second stage 196, etc. to a predetermined energy level to generate electron beam 198. The electron beam 198 is then transmitted to wiggler 182 Bending magnet 2oo applied. The exiting electron beam

202 is connected to the entrance of Catalac 186 via bending magnet

203 and an achromatic isochronous (not shown) Radiation transport system created. Catalac 186 and subsequent auxiliary Catalacs contain within a multitude of successive stages extracting predetermined amounts of energy from the various energy levels of the Electrons of the electron beam 2o2. A variety of electron spectrometers, such as electron spectrometers 2o4 and 2o6 eliminate the low-energy electrons,

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after enough energy has been extracted from these that they do not continue through the auxiliary Catalacs can. Again, recovered energy is used to accelerate the electron beam generated by injector 184 used.

Fig. 15 shows a ring resonator for use with various embodiments disclosed in FIGS. 5 to 7 and 9 to 14. Since the amplification of coherent light is only achieved when photons of the resonator travel in the same direction as the electron beam it is often advantageous to use a ring resonator, for example shown in Fig. 15 to use where photons 2o8 are conducted in a closed loop pattern, through reflectors 21o, 212, 214 and 216, so that they pass through wiggler 218 in the direction of electron beam 22o only. The electron beam 22o is through Bending magnets 222 and 224 passed through wiggler 218 and then through bending magnets 226 and 228, so in the closed Loop pattern of the type described above to continue on its way. The output reflector 216 produces a laser output 218, which is guided along the optical axis of the wiggler 218. Of course, the exit reflector can 216 somewhere within the ring resonator according to FIG. 15 be arranged to direct the output beam in different directions.

Figure 16 shows the use of an input laser beam from a master oscillator in conjunction with the Catalac free Electron laser according to the invention for eliminating the optical resonators shown in FIGS. 6, 7 and 9 to 15, so as to convert the Catalac-free electron laser oscillator according to FIGS. 6, 7 and 9 to 15 into a Catalac

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convert free electron laser amplifier. Operational the electron beam 234 is guided by wiggler 236 via bending magnets 238 and 24o. The main oscillator laser 242 generates an optical signal at a specific frequency at which the free electron laser amplifier is tuned is. After passing through wiggler 236, the input laser beam 232 is amplified to form an amplified output beam 244 to generate. Any desired injection laser 242 can be used in this manner, including, but not limited to free electron laser oscillators, HP lasers, mode-locked neodymium YAG lasers, etc. The tunable ones The nature of the free electron laser gives a wide range of uses for the free electron laser amplifier, in conjunction with other lasers including high power gas molecular lasers.

The invention therefore provides a free electron laser with high efficiency, which is based on the developed and reliable HF acceleration technology based. The inventive Catalac-free electron laser is in the Able to deliver high efficiency at wavelengths shorter than the near IR using a Electron beam power system that eliminates electrons, after energy has been extracted from these electrons to solve problems such as beam divergence, to eliminate the torque distribution, etc. that occur in storage ring devices and in a serious manner the electron beam quality and the performance of the free electron laser. The free electron laser according to the invention uses a linac which acts as a catalyst to reduce the electron energy from electrons emerging from the free electron laser to transform directly into acceleration field energy in order to

130036/0697

ORIGINAL JNSPECTED

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30A69Q9

to accelerate new electrons, which gives both high efficiency and easy operation.

The above description is not intended to be construed in a restrictive manner. Modifications are possible. For example the bending magnets and the radiation transport systems of the type shown can be a single integrated unit, to transport the beam in an isochronous and achromatic manner according to known beam transport principles. Although the elements for bending and transporting the beam are shown only schematically, it is clear that aie work according to known principles.

130036/0697

Claims (1)

Expectations (Ty free electron laser for amplifying coherent radiation / gek e η η ζ ei σ h η e t by means for generating a beam of electrons, means for accelerating the beam of electrons a predetermined relativistic energy using RF acceleration fields, Wiggler means for inducing transverse oscillations in the beam of electrons to amplify the coherent ones Radiation, Means for guiding the beam of electrons emerging from the wiggler into the means for acceleration, thereby making the electrons of the beam of electrons coming out the wiggler exits, out of phase with the RF acceleration fields, so energy from the electrons into energy to transform the acceleration fields, so as to increase the efficiency of the laser to increase. 2. Laser according to claim 1, characterized by an optical resonance cavity aligned with the wiggler means for feedback of the coherent optical Radiation, generated and amplified in the wiggler means. 130036/0697 3. Laser according to claim 1 and / or 2, characterized by means for separating the low-energy electrons from the high energy electrons. 4. Laser according to one of the preceding claims, in particular according to claim 1, characterized in that that the optical resonance cavity comprises a ring resonator. 5. Free electron laser, characterized by Means for generating an electron beam, wiggler means for inducing transverse vibrations in the electron beam, Means for guiding the electron beam in a closed loop, Catalac acceleration / deceleration means for accelerating the electron beam during an initial pass through the Catalac acceleration / deceleration means and for decelerating the electron beam during a second pass through the Catalac acceleration / deceleration means for extracting energy from the electron beam and for transformation of this energy · - \ 1 ¹ ^ - acceleration fields of the Catalac acceleration / deceleration means. 6. The laser of claim 5 characterized by resonant optical cavity means aligned with the wiggler means for the feedback of coherent optical radiation, generated and amplified in the wiggler means. 130036/0697 ORiGlNAL INSPECTED 7. Laser according to one or more of the preceding
Claims, in particular according to claim 5, characterized by an external source more coherent
Radiation aligned with the wiggler means. 8. Laser according to one or more of the preceding
Claims, in particular according to Claim 5, characterized by means for separating the low-energy electrons from the high-energy electrons. 9. Laser according to claim 6, characterized in that that the optical resonance cavity comprises a ring resonator. 1o. The free electron laser of claim 5 further
marked by: additional Catalac acceleration / deceleration means
to further accelerate the electron beam during the initial pass through the Catalac acceleration / deceleration means and an initial pass through the additional Catalac acceleration / deceleration means, and to further extract energy from more
as an energy level from the electron beam during
the second pass through the Catalac acceleration / deceleration means and a second pass through the additional Catalac acceleration / deceleration means. 11. Free electron laser system with a wiggler
for extracting energy from a beam of electrons at a predetermined energy level to generate coherent optical radiation, whereby an electron beam power 130036/0697 System for the free electron laser system has the following: Means for generating the beam of electrons, HP cavity means for accelerating and decelerating the Beam of electrons, Means for directing the electron beam through the RF cavity means to accelerate the electron beam to the predetermined energy level and to delay the After exiting the wiggler, the electron beam is used to extract energy from the electron beam and to transform it this energy in accelerating fields of the RF cavity means, increasing the efficiency of the electron beam power system is enlarged. 12. Electron beam power system according to claim 11, characterized by means for separation the low-energy electrons from the high-energy electrons and to eliminate the low-energy electrons from the Conduction means. 13. electron beam power system according to claim 11, characterized by additional RF cavity means to accelerate and decelerate the electron beam to further extract energy to more as a level from the electron beam exiting the wiggler. 14. Free electron laser system with a wiggler for Extraction of energy from an electron beam at a predetermined energy level to produce more coherent optical Radiation, being an electron beam power system 130026/0697 $ 304,690 for the free electron laser has the following: means for generating the electron beam, Means for guiding the electron beam in a closed loop, Catalac acceleration / deceleration means for accelerating the electron beam to the predetermined energy level to contact the wiggler and to delay the electron beam, exiting the wiggler to extract energy from the electron beam and transform this energy in acceleration field of the Catalac acceleration / Delay Means. 15. Electron beam power system according to claim 13, characterized by means for separating the Low-energy electrons from the high-energy electrons and to eliminate the low-energy electrons from the conducting means. 16. Electron beam power system according to claim 14, characterized by additional Catalac acceleration / deceleration means to further extract energy at more than one energy level from the off the electron beam exiting the wiggler. 130036/0697